how to calibrate a tachometer

• 2023-07-21

The speed is a barometer of the engine's operating state. When the engine is idling and in neutral, the speed should be stable and within a reasonable range; When pressing the accelerator pedal in neutral, the speed should change smoothly with the smooth rise and fall of the pedal . When stabilizing the accelerator pedal, the tachometer pointer should remain at a certain speed scale . If the engine idle speed is too high or too low , the speed is unstable , and the tachometer shakes , it indicates that the engine is malfunctioning. As a reference for shifting of manual transmission, select the appropriate shifting time to make the engine work in the most economical working range.

The calibration steps for a tachometer are as follows:

1.Firstly, start the engine, fully open the choke valve, and then slowly unscrew the throttle limit screw to reduce the throttle opening and reduce the engine speed to the lowest stable speed.
2.Adjust the idle adjustment screw to increase the engine speed as much as possible.
3.Slowly unscrew the throttle limit screw again to lower the engine speed back to the specified minimum stable speed (approximately 800-900 r/min). By repeatedly adjusting this, the throttle opening can be adjusted to the minimum.

How to determine the tachometer: Open the car dashboard display. The left most tachometer dial has Arabic numerals 1 to 8, with the words x1000rpm in the middle, indicating that the engine speed at this time is: the pointer reading multiplied by 1000rpm, for example, the engine speed shown in the figure is 800-900rpm. In addition, the speed indication of some models is x100 rpm; The corresponding dialing number is a two digit 10, 20, 30, and the meaning of the multiplication expression remains the same.

We also need to pay attention to the speed when driving. If the speed is too high (4000r/min), it will be more expensive. If we reach the red line, it will also cause permanent damage to the engine and the car. Fortunately, most engines have a speed limit function, which prevents you from driving a family car like a racing car. In summary, a tachometer is used to monitor the working status of the engine, allowing you to understand it in real-time. For experienced drivers, listening to the sound and looking at the watch can determine where the car is malfunctioning.